Alloy



Patented Apr. 8, 1941 ALLOY Jacob Trantin, Jr., Youngstown, Ohio No Drawing. Application March 28, 1940, Serial No. 326,429

3 Claims.

This invention relates to steel alloys capable of being cast, and more particularly, is concerned with alloys having high wear resistance and freedom from scale pickup and specifically adapted to use as guides in a hot bar rolling mill.

Heretofore in rolling bars while hot, guides of white or gray cast iron have been employed to position the bars and to direct them properly into the rolls. However, such cast iron guides have a relatively short life and are quite subject to scratching, wear and deposition of hot scale on them. Scratched or marred guides, as by scale or otherwise, often objectionably mar the work. Attempts have been made to heat treat or harden the cast iron guides as by casting them against a chill all without solving the existing problem. Further, efforts have been made to employ other materials as guides. However, because of brittleness, lack of wear resistance, or susceptibility to scale deposition none of the experiments with other materials have provensuccessful and the cast iron guide with all its faults is still employed.

It is the general object of my invention to provide an improved guide for directing and controlling metal bars in the hot rolling thereof.

Another object of my invention is the provision of an improved steel alloy capable of being cast and characterized by wear resistance and lack of susceptibility of metal deposit thereon.

Another object of my invention resides in providing a castable steel alloy particularly subject to controlled heat treatment whereby .a cast article can be given a desired hardness greater than its hardness in an annealed state.

' The foregoing and other objects of my invene. tlon are achieved by the provision of a bar mill guide of cast steel having over about 5.00 percent chromium'therein, and over about 1.50 percent copper therein. More completely, I provide a castable steel alloy having a composition including between about 1.00 andabout 1.50 percent carbon, about .40 to about 1.00 percent manganese, about .40 to about 3.00 percent silicon, about 5.00 to about 30.00 percent chromium, up to about 1.00 percent molybdenum. up to about .50 percent vanadium, and between about 1.50 and about 5.00.

percent copper.

Although my improved alloy is useful in many relations and wherever wear resistance and lack of susceptibility to metal or other deposit are important, nevertheless, my invention is particularly adapted to and concerned with the provision of improved means for forming or guiding hot metal during rolling or forming, and specifically is concerned with providing guides for mills for rolling hot bars.

According to my invention I provide a steel alloy having an analysis including between about 1.00 and about 1.50 percent carbon, about .40 to about 1.00 percent manganese, about .40 to about 3.00 percent silicon, about 5.00 to about 30.00 percent chromium, between about 1.50 and about 5.00 percent copper, and the remainder substantially iron. Usually I prefer to have up to about 1.00

percent molybdenum and up to about .50 percent vanadium. The usual percentages of sulphur and phosphorus present in open hearth or Bessemer commercial steels are not objectionable nor are traces of nickel, tungsten or other alloying agents or impurities. Further, it should be understood that increasing the manganese content of my alloy permits a decrease in the chromium content and vice versa. Also, I may use tungsten in place 01 the molybdenum and I may reduce the carbon content below the limits indicated to avoid brittleness. Other variations in the exact composition of my alloy to achieve a desired or a particular result, all as well known to those skilled in the art, may be resorted to without departing from the basic concept of any invention.

One guide for bar mills which possessed the desired characteristics of long wear and lack of susceptibility to scale deposition comprised the following composition: carbon 1.15 percent; manganese .45 percent; silicon 1.61 percent; chromium 14.56 percent; molybdenum .40 percent; vanadium .035 percent; copper 2.34-percent and the balance substantially iron.

Preferably I add the copper to the alloy during the end of the melt or to the ladle in order to avoid oxidation. However, the copper may be put in the batch initially in sufiicient quantities to allow for oxidation loss.

An important feature of my invention resides in the provision of a castable steel alloy which lends itself to controlled heat treatment. Specifically,- I am able to obtain relatively wide degrees of hardness in my improved alloy by controlled heat treatment with standard heat treating methods. Thus, while my alloy has many advantageous and desirable characteristics in an annealed state, its hardness can be increased by appropriate heat treatment to best adapt it for any given use. For example, in making a bar mill guide I raise the temperature of the guide after casting'to about 1850 degrees Fahrenheit or more and oil quench.

I The resulting Brinell is in excess of 350, but without obtaining an undesirable Charpy value.

From the foregoing it will be recognized that the objects of my invention have been achieved and that I have provided a castable steel alloy particularly adapted to act as a guiding or forming member for hot metal and characterized by wear resistance and long life without the deposition thereon of scale. In fact, the bar mill guides of my invention have in commercial operation outlasted the usual cast iron guide many times over and in onegiven installation over five million pounds of steel has been passed over a set of guides without the guides having to be touched during a turn. Between turns, on only four occasions the guides were removed, dressed and returned to duty.

Although in accordance with the patent statutes I have particularly described my invention, it will be understood that I am not to be limited thereto or thereby, but that the scope of my invention is defined in the appended claims.

I claim:

1. A guide for metal bars during hot rolling thereof in amill, said guide being of caststeel having an analysis including between about 1.00 and about 1.50 per cent carbon, about .40 to about 1.00 per cent manganese, about .50 to about 3.00

per cent silicon, about 5.00 to about 30.00 per cent chromium, up to about 1.00 per cent molybdenum,

up to about .50 per cent vanadium, between about 1.50 and about 5.00 per cent copper, and the remainder substantially all iron, said guide having a hardness greater than its hardness in an annealed state, and being characterized by wearresistance and freedom from scale pickup.

2. An alloy comprising between about 1.00 and about 1.50 per cent carbon, about .40 to about 1.00 per cent manganese, about .50 to about 3.00 per cent silicon, about 5.00 to about 30.00 per cent chromium, up to about 1.00 per cent molybdenum, up to about .50 per cent vanadium, between about 1.50 and about 5.00 per cent copper, and the remainder substantially all iron, said alloy being capable of being cast, and being characterized by hardness and freedom from scale pickup.

3. An alloy comprising about 1.00 per cent carbon, about .45 per cent manganese, about 1.60 per cent silicon, about 15.00 per cent chromium, about .40 per cent molybdenum, about .035 per cent vanadium, about 2.50 per cent copper, balance substantially all iron.

JACOB TRANTIN, J R.

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